/*
 * 检测用户错误输入（4分）
 */

#include <stdio.h>

int main() {
	setbuf(stdout, NULL);

	int get_scanf_return, a, b;

	get_scanf_return = scanf("%d %d", &a, &b);

	if (get_scanf_return != 2) {
		printf("Input error!\n");
		return -2;
	} else {
		printf("a = %d, b = %d\n", a, b);
	}

	return 0;
}